I. Field of the Invention
This disclosure relates generally to apparatus and methods for position estimation of wireless terminals, and more particularly to generating positioning assistance data from multiple LCI maps.
II. Background
Building maps inform a user the location of walls, room, entrances, stairs, elevators, rooms, portals and the like. A positioning engine may use these building maps to determine where and how a particle, that is, a mobile phone, may move through a building. A navigation engine may use the building map to define a particle map having boundaries for inertial navigation thereby creating RF heat models for RF propagation. As a result, particle maps from building maps lead to improved positioning estimates.
Maps for a common venue may come from multiple sources and include different types of information. Various sources of original maps supply competing or similar maps of common venues. For example, multiple maps may provide drawings of a particular indoor mall. A first map may include an outline of shops and stores within an indoor mall with each shop and store being labeled. A second map may include interior walls of the indoor mall. A third map may include structural walls and supports of the mall. The various maps may serve different purposes. For example, one map may provide routing, another map may provide points of interest (POI), a third map architectural structure, a fourth map may provide topology, and so on. Some maps are from one or more computer aided design (CAD) files. For example, a CAD file from a facilities manager may show furniture and room numbers, while an architect's CAD file shows a building's footprint, structure and support walls without furniture.
Sometimes a larger building is split into two or more adjacent maps where different floors and/or wings are sections of a building each having its own maps. As an example, a CAD file exists for the East wing first floor of a building while another CAD file exists for the West wing first floor and yet another CAD file exists for a second floor of the same building.
Such maps may of an entire building or a distinguishable logical section of a building (e.g., a single wing or floor) may be referred to as location content. The location content may be indexed or referred to at a location context identifier (LCI). A first LCI may index an entire floor of a particular building (e.g., a first map 110). A second LCI may index a second floor of the particular building (e.g., a second map 120). A set of LCIs may index various wings of a different building. Therefore, some buildings have a single LCI indexing a single floor plan while other buildings have multiple LCIs each corresponding to a different logical section of the building. Still other buildings have no LCI index to a floor plan.
What is needed is a means to merge these similar and adjacent maps of a common venue into an overall robust and complete merged map that better defines an area. A better define LCI allows improved prediction of how a particle may move within and between such maps and how RF signals propagate from access points. These maps result in positioning assistance data for a mobile device that better allows for a more accurate positioning estimate.